M156 tuning

[Joshinator99]

Hi,
I have a 2009 ML 63 AMG with the 6.2L NA V8. Currently stock. I pulled the secondary charcoal air filters out of the two air boxes and am now getting MAF codes. Looks like this truck has dual widebands from the factory, so easy to just tune AFR correction to the MAF scales to compensate? Or am I just better off buying the ROW (Rest Of World) air boxes anyway and going that route (they do not have the charcoal air filters). I understand they supposedly flow more air anyway.

[Josue Galban]

Hi,
I have a 2009 ML 63 AMG with the 6.2L NA V8. Currently stock. I pulled the secondary charcoal air filters out of the two air boxes and am now getting MAF codes. Looks like this truck has dual widebands from the factory, so easy to just tune AFR correction to the MAF scales to compensate? Or am I just better off buying the ROW (Rest Of World) air boxes anyway and going that route (they do not have the charcoal air filters). I understand they supposedly flow more air anyway.

MAF its perfect to amg

[Joshinator99]

MAF its perfect to amg

I’m afraid I don’t understand what you’re saying…

[TheMechanic]

Not familiar with the system at all but most MAF are corrected for a laminar air flow. Anything that can cause that flow to tumble or have high a low pressure areas throughout the load range can drastically effect MAF calibration. As to whether you can "tune it" out I don't see any reason you can't. In your scanner make sure you have a good refresh rate and wideband and you should be good to go on tuning.

[Joshinator99]

Not familiar with the system at all but most MAF are corrected for a laminar air flow. Anything that can cause that flow to tumble or have high a low pressure areas throughout the load range can drastically effect MAF calibration. As to whether you can "tune it" out I don't see any reason you can't. In your scanner make sure you have a good refresh rate and wideband and you should be good to go on tuning.

Thanks. The truck is factory equipped with dual widebands which is pretty impressive for a 2009 vehicle!

I think you’re right about the laminar flow issue. I suspect the charcoal filters helped slow & straighten the airflow through the MAF and it’s causing the issue. Going to investigate the larger air boxes used in the “Rest of World” versions since they did not come with the charcoal filters at all and the MAF Venturi is bigger.

[TheMechanic]

I have been walking the planet for a while so I remember the charcoal put into air cleaners a long time ago to reduce fuel vapor emissions on shutoff. Figured they would have got that figured out by now with maybe some elevated idle, open throttle to purge vapors on shutoff. Obviously they must have had a problem or some new tighter standard.

[veeefour]

Yeah they come with widebands but they dont run fully in Closed Loop...early merc logic...

What kind of codes you are having there?

[Joshinator99]

Yeah they come with widebands but they dont run fully in Closed Loop...early merc logic...

What kind of codes you are having there?

Ah, interesting. So they’re wideband sensors but do not do WOT fuel trim? I’m assuming I could still use them for tuning purposes though, right?

So I pulled the charcoal filters from the air boxes and got P010B and P0101 MAF related codes. The profile on the US-spec air boxes suck and apparently the additional airflow causes too much turbulence in the box for the MAF to read cleanly. I noticed bucking and stumbling at high load/low rpm use (highway speeds). So I ordered the fix: “Rest Of World” air boxes that never came with charcoal filters. I’m told by an experienced M156 shop that these ROW air boxes are plug and play.

To be clear, I’m not opposed to tuning it, but I’m assuming it might be different than tuning my Camaro lol… And having the better airboxes seem like a smart move regardless.

[Joshinator99]

I have been walking the planet for a while so I remember the charcoal put into air cleaners a long time ago to reduce fuel vapor emissions on shutoff. Figured they would have got that figured out by now with maybe some elevated idle, open throttle to purge vapors on shutoff. Obviously they must have had a problem or some new tighter standard.

Yeah my wife’s new Mustang came with a charcoal filter in addition to the regular filter. Although on her car I was able to launch it all for a nice CAI with no tune needed.

[veeefour]

Ah, interesting. So they’re wideband sensors but do not do WOT fuel trim? I’m assuming I could still use them for tuning purposes though, right?

So I pulled the charcoal filters from the air boxes and got P010B and P0101 MAF related codes. The profile on the US-spec air boxes suck and apparently the additional airflow causes too much turbulence in the box for the MAF to read cleanly. I noticed bucking and stumbling at high load/low rpm use (highway speeds). So I ordered the fix: “Rest Of World” air boxes that never came with charcoal filters. I’m told by an experienced M156 shop that these ROW air boxes are plug and play.

To be clear, I’m not opposed to tuning it, but I’m assuming it might be different than tuning my Camaro lol… And having the better airboxes seem like a smart move regardless.

Yes but only to tell - not going to to correct anything under power enrichment...oh wait it does not have any typical PE...

MAF is there only for diagnostic and plausibility - normally it runs on MAP.

I had a brain storm tuning this engine with Magnusson supercharer with bigger injectors etc...but made its trough and it nothing like you seen in US based cars.